1. Field of the Invention
Embodiments of the present invention relate generally to a bioreformation of complex to produce glucose as a fuel. More particularly, the present invention relates to a bioreactor for converting sucrose or fructose into glucose through an enzymatic cascade process within a series of packed columns.
2. Related Art
In recent years implanted therapeutic medical devices have become increasingly important. Devices such as cardiac and brain pacemakers, insulin and chemotherapy pumps, left ventricular assist devices (“LVAD”), cochlear implants, and various implanted blood sensors are routinely used to assist patients who are chronically ill. These devices, however, require a source of power, typically implanted batteries which must be removed and replaced periodically. Because battery replacement can place the user in medical jeopardy, use of fuel cells, wherein the body's own supply of glucose sugar is utilized as the energy source, has been a current area of active investigation (e.g., U.S. Pat. Nos. 6,294,281 and 6,503,648).
However, one of the primary limitations of biologically inspired fuel cells is the quantity and quality of fuel feedstock that can be provided to it. In those applications where only complex sugars such as sucrose or fructose, are available instead of glucose, an efficient means for converting sucrose or fructose to glucose would be advantageous. This converter output would then serve as a fuel stream input to power a mechanical/electrical device.
The present concept, therefore, discloses an enzymatic cascade approach for direct reduction of sucrose and fructose into glucose. The design is based on a “flow-through” fuel reformation reactor which utilizes an enzymatic “cascade” for converting sucrose and fructose into glucose. The approach uses three packed columns linked in series wherein an inlet stream comprising a sucrose solution first passes through a matrix comprising invertase which converts the sucrose to a solution comprising fructose and α-D-glucose. This converted solution then passes through a second matrix comprising glucose isomerase which converts the fructose into β-D-glucose. Lastly, the solution passes through a third matrix comprising mutarotase which converts the α-D-glucose fraction to β-D-glucose. The three matrices comprising the three immobilized enzymes are flow-through columns packed with a plurality of porous silica particles whose surfaces have been modified so as to bind to amine sites on each of the enzymes, thereby immobilizing each specific enzyme-type to the silica particle surfaces.
This approach enables deploying a glucose-based fuel cell into environments that possess an abundance of sucrose and/or fructose but have minimal glucose (i.e., plants, trees). Moreover, the concept of an enzymatic cascade is also relevant in the field of alternative fuel production (ethanol) and carbon sequestration, where the use of such a system could prove to be revolutionary in terms of process engineering, cost benefit, and efficiency.
Related art comprise patents to Catani, et al. (U.S. Pat. Nos. 6,660,502, and 5,998,177) who disclose a process for forming glucose and fructose from sucrose wherein an enzyme is immobilized by absorption on a granular carrier having a primary to quaternary amine, and wherein the carrier is an epoxy polymer, a vinyl polymer, or a chitosan derivative having a primary, secondary or tertiary amine. Further, Tayot, et al., (U.S. Pat. No. 5,234,991) disclose a porous support such as silica which is coated with an aminated polysaccharide polymer; Le Favre, et al., (U.S. Pat. No. 5,998,183) disclose a method for immobilizing enzymes on silica gels and alumino-silicates using glutaraldehyde; and Ho, et al., (U.S. Pat. No. 4,384,045) disclose a method for activating the surface of siliceous surfaces to improve attachments of enzymes. Lastly, Wilkins (U.S. Pat. No. 5,476,776) discloses an electrochemical sensor utilizing enzymes immobilized on particulate matter including silicon and aluminum oxides.